Saturday, September 18, 2021

[Ichthyology • 2021] A Taxonomic Review of the Family Trachipteridae (Acanthomorpha: Lampridiformes), with An Emphasis on Taxa Distributed in the western Pacific Ocean

Zu sp. 

in Martin & Hilton, 2021. 
photographed in Nusa Penida, Indonesia by Helen Mitchell

The family Trachipteridae—the Ribbonfishes, Dealfishes, and their relatives—has a circumglobal distribution, with at least 10 species in three genera (Zu Walters & Fitch 1960, Desmodema Walters & Fitch 1960, and Trachipterus Goüan 1770) that are characterized by elongate, extremely laterally compressed bodies, large eyes, absence of ribs, spines on lateral-line scales, greatly protrusible mouths, and a lack of pelvic fins in adults. They are also known for the drastic morphological changes that occur during ontogeny. Trachipterids are poorly represented in collections due to the fragile nature of their bodies. Most studies of the Trachipteridae have been limited by the numbers, developmental stages, and the completeness of the specimens that were examined. Along with the lack of available material, incomplete and conflicting character information compounds the taxonomic confusion of Trachipteridae. Despite the body of regional revisions that have examined trachipterid taxonomy, none have synthesized a suite of morphological characters across ontogeny. The goals of this paper are to (1) revise the family Trachipteridae, (2) revise the genera Trachipterus, Zu, and Desmodema, including information regarding ontogeny and biogeography, and 3) address the alpha taxonomy of Zu, Desmodema, and Trachipterus from the western Pacific Ocean. We recognize possibly five species of Trachipterus as being present in the western Pacific, as well as two species of both Zu and Desmodema. Despite additions to the specimen base that allows refinement of taxonomy and diagnoses, there are still large knowledge gaps associated with the taxonomic review of Trachipteridae. These reflect incomplete understanding of geographic distribution of taxa which may mask unrecognized taxonomic variability. The genus Trachipterus specifically remains problematic and will require greater detailed global study. Early life history stages remain unknown for several taxa which hinders full interpretation of ontogenetic transitions. Protracted transitions, some of which are clarified here, further confuse stage-based diagnoses and must be considered in future analyses of this family.
Keywords: Pisces, Ribbonfishes, Trachipterus, Desmodema, Zu, ontogenetic characters 

Order Lampridiformes Goodrich 1909
Family Trachipteridae Swainson 1839
Ribbonfishes, Dealfishes

Trachipterus Goüan 1770

Putatively valid taxa in the western Pacific Ocean 
1. Trachipterus trachypterus (Gmelin 1789). Holotype: No types known. Mediterranean. 
2. Trachipterus altivelis Kner 1859. Syntype: NMW 22046. Valparaiso, Chile. Unavailable for examination in current study.
3. Trachipterus arawatae Clarke 1881. Holotype NMNZ P.1008, 51 cm SL. Hominy Cove, Jackson’s Bay New Zealand. Examined.
4. Trachipterus jacksonensis (Ramsay 1881). Syntype: AMS A.9114, 1408 mm, caudal missing (736 mm SV). Manly Beach, Port Jackson, New South Wales, Australia. Examined.
5.  Trachipterus ishikawae Jordan & Snyder 1901. Holotype: NSMT 589, 1250 mm SL. Off the mouth of Tokyo Bay, between Misaki and Boshu. Examined.

Zu sp. Live specimen (not collected) photographed in Mallorca, Spain.
photo: Michael Makowiecki.

Zu sp. Live specimen (not collected) photographed in Nusa Penida, Indonesia.
photo: Helen Mitchell.

Zu Walters & Fitch 1960

Zu cristatus (Bonelli 1820)
Zu elongatus Heemstra & Kannemeyer 1984

Desmodema Walters & Fitch 1960

Desmodema polystictum (Ogilby 1898)
Desmodema lorum Rosenblatt & Butler 1977

Despite advances in the understanding of Trachipteridae resulting from tremendous additions to the specimen base, which have allowed for the refinement of the taxonomy and diagnoses within the family, there are still large knowl-edge gaps associated with the taxonomy of the family. These reflect incomplete understanding of geographic dis-tribution of taxa that may mask unrecognized taxonomic variability. The genus Trachipterus specifically remains problematic and will require greater detailed global study. Early life history stages remain unknown for several taxa, which hinders full interpretation of ontogenetic transitions. Protracted transitions, some of which are clarified here, further confuse stage-based diagnoses and must be considered in future analyses of this family.

Jennifer M. Martin and Eric J. Hilton. 2021. A Taxonomic Review of the Family Trachipteridae (Acanthomorpha: Lampridiformes), with An Emphasis on Taxa Distributed in the western Pacific Ocean. Zootaxa. 5039(3); 301-351. DOI: 10.11646/ZOOTAXA.5039.3.1

[Paleontology • 2021] Growth and Miniaturization among Alvarezsauroid Dinosaurs

representative alvarezsauroids, Haplocheirus sollers (left), Patagonykus puertai (upper middle), Linhenykus monodactylus (lower middle), 
illustrating the body size and dieting change in alvarezsauroid dinosaurs.

in Qin, Zhao, ... et Xu, 2021.
Reconstruction: Zhixin Han/
• How and why the bizarre alvarezsauroid dinosaurs miniaturized is poorly known
• We reveal a rapid Late Cretaceous alvarezsauroid miniaturization and radiation
• Osteohistological data show highly variable growth strategies among alvarezsauroids
• Alvarezsauroid miniaturization is possibly associated with adaptations to digging

Sustained miniaturization, here defined as a drop in body size of at least two orders of magnitude from ancestors to descendants, is a widespread and important phenomenon in animals but among dinosaurs, miniaturization occurred only rarely, once in the lineage leading to birds and once in the Alvarezsauroidea, one of the most bizarre theropod groups. Miniaturization and powered flight are intimately linked in avialan theropods but the causes and patterns of body size reduction are less clear in the non-volant Alvarezsauroidea. Here, we present results from analyses on a comprehensive dataset, which not only includes new data from early-branching alvarezsauroids but also considers the ontogenetic effect based on histological data. Our analyses show that alvarezsauroid body mass underwent rapid miniaturization from around 110 to 85 mya and that there was a phylogenetic radiation of small-sized alvarezsauroids in the Late Cretaceous. Our analyses also indicate that growth strategies were highly variable among alvarezsauroids, with significant differences among extremely small taxa. The suggested alvarezsauroid miniaturization and associated phylogenetic radiation are coincident with the emergence of ants and termites, and combining previous functional morphological data, our study suggests that alvarezsauroid miniaturization might have been driven by ecological changes during the Cretaceous Terrestrial Revolution, more specifically by a shift to the myrmecophagous ecological niche.
Keywords: growth strategy, growth rate, body size evolution, miniaturization, alvarezsauroid dinosaurs, ontogenetic effect, osteohistology, phylogenetic radiation, Cretaceous Terrestrial Revolution, ecological niche

four representative alvarezsauroids, Haplocheirus sollers (left), Patagonykus puertai (upper middle), Linhenykus monodactylus (lower middle) and Bannykus wulatensis (lower right), illustrating the body size and dieting change in alvarezsauroid dinosaurs.
Reconstruction: Zhixin Han/

 Zichuan Qin, Qi Zhao, Jonah N. Choiniere, James M. Clark, Michael J. Benton and Xing Xu. 2021. Growth and Miniaturization among Alvarezsauroid Dinosaurs. Current Biology. 31(16); 3687-3693.e5. DOI: 10.1016/j.cub.2021.06.013

[Paleontology • 2020] A Paraphyletic ‘Silesauridae' as An Alternative Hypothesis for the Initial Radiation of Ornithischian Dinosaurs

in Müller & Garcia, 2020.

Whereas ornithischian dinosaurs are well known from Jurassic and Cretaceous deposits, deciphering the origin and early evolution of the group remains one of the hardest challenges for palaeontologists. So far, there are no unequivocal records of ornithischians from Triassic beds. Here, we present an alternative evolutionary hypothesis that suggests consideration of traditional ‘silesaurids' as a group of low-diversity clades representing a stem group leading to core ornithischians (i.e. unambiguous ornithischians, such as Heterodontosaurus tucki). This is particularly interesting because it fills most of the ghost lineages that emerge from the Triassic. Following the present hypothesis, the lineage that encompasses the Jurassic ornithischians evolved from ‘silesaurids' during the Middle to early Late Triassic, while typical ‘silesaurids' shared the land ecosystems with their relatives until the Late Triassic, when the group completely vanished. Therefore, Ornithischia changes from an obscure to a well-documented clade in the Triassic and is represented by records from Gondwana and Laurasia. Furthermore, according to the present hypothesis, Ornithischia was the first group of dinosaurs to adopt an omnivorous/herbivorous diet. However, this behaviour was achieved as a secondary step instead of an ancestral condition for ornithischians, as the earliest member of the clade is a faunivorous taxon. This pattern was subsequently followed by sauropodomorph dinosaurs. Indeed, the present scenario favours the independent acquisition of an herbivorous diet for ornithischians and sauropodomorphs during the Triassic, whereas the previous hypotheses suggested the independent acquisition for sauropodomorphs, ornithischians, and ‘silesaurids'.

Keywords: evolution, Dinosauria, Mesozoic era, phylogenetics, feeding behaviours, Dinosauromorpha 

Rodrigo Temp Müller and Maurício Silva Garcia. 2020. A Paraphyletic ‘Silesauridae' as An Alternative Hypothesis for the Initial Radiation of Ornithischian Dinosaurs. Biology Letters. 16:20200417. DOI: 10.1098/rsbl.2020.0417

Sacisaurus helps to fill the hole in the evolution of ornithischians

[PaleoOrnithology • 2021] Yuanchuavis kompsosoura • An Early Cretaceous enantiornithine Bird with A Pintail

  Yuanchuavis kompsosoura 
Wang, O’Connor, Zhao, Pan, Zheng, Wang & Zhou, 2021

Illustration: Haozhen Zhang 

• Wang et al. describe a new pengornithid enantiornithine from the Early Cretaceous
• The new enantiornithine specimen preserves a pintail indicative of sexual selection
• The exaggerated pintail of this fossil bird may arise from the handicap process
 • Mesozoic enantiornithines and ornithuromorphs show contrasting tail morphotype

Enantiornithes are the most successful group of Mesozoic birds, arguably representing the first global avian radiation, and commonly resolved as the sister to the Ornithuromorpha, the clade within which all living birds are nested. The wealth of fossils makes it feasible to comparatively test evolutionary hypotheses about the pattern and mode of eco-morphological diversity of these sister clades that co-existed for approximately 65 Ma. Here, we report a new Early Cretaceous enantiornithine, Yuanchuavis kompsosoura gen. et sp. nov., with a rectricial fan combined with an elongate central pair of fully pennaceous rachis-dominated plumes, constituting a new tail plumage previously unknown among nonavialan dinosaurs and Mesozoic birds but which strongly resembles the pintail in many neornithines. The extravagant but aerodynamically costly long central plumes, as an honest signal of quality, likely evolved in enantiornithines through the handicap process of sexual selection. The contrasting tail morphotypes observed between enantiornithines and early ornithuromorphs reflect the complex interplay between sexual and natural selections and indicate that each lineage experienced unique pressures reflecting ecological differences. As in neornithines, early avialans repeatedly evolved extravagant structures highlighting the importance of sexual selection in shaping the plumage of feathered dinosaurs, even early in their evolutionary history.

Keywords: Aves, dimorphism, Enantiornithes, feather, phylogeny, Mesozoic, Ornithuromorpha, sexual selection



  Yuanchuavis kompsosoura gen. et sp. nov.

 Min Wang, Jingmai K. O’Connor, Tao Zhao, Yanhong Pan, Xiaoting Zheng, Xiaoli Wang and Zhonghe Zhou. 2021. An Early Cretaceous enantiornithine Bird with A Pintail. Current Biology. In Press. DOI: 10.1016/j.cub.2021.08.044

Friday, September 17, 2021

[PaleoOrnithology • 2021] Kairuku waewaeroa • A Giant Oligocene Fossil Penguin (Aves: Sphenisciformes) from the North Island of New Zealand

 Kairuku waewaeroa   
Giovanardi, Ksepka & Thomas, 2021

Penguins (Sphenisciformes) have arguably the most complete and continuous fossil record of any avian clade, offering an ever-improving understanding of penguin phylogeny, biogeography, and the evolution of wing-propelled diving. Yet, our knowledge of the precise body proportions of stem-group penguins remains poor due to a dearth of articulated specimens. Here, we describe Kairuku waewaeroa sp. nov., a new giant penguin species from the Glen Massey Formation (Whaingaroan stage, 34.6–27.3 Ma). The holotype skeleton, discovered in Kawhia Harbour, North Island, New Zealand, is one of the most complete skeletons of a giant penguin yet uncovered. Our phylogenetic analysis recovers a clade uniting the New Zealand endemics Kairuku waewaeroa, Kairuku waitaki, and Kairuku grebneffi, which is supported by synapomorphies including a stout femoral shaft and tibiotarsi with a distinctly convex medial condyle. Kairuku waewaeroa is unique among stem penguins in having elongate tibiotarsi, revealing a new long-legged stem penguin body plan. The discovery of Kairuku waewaeroa contributes yet another penguin species to an Oligocene avifauna for Zealandia that is replete with giant birds.

Kairuku waewaeroa sp. nov. 
Simone Giovanardi, Daniel T. Ksepka and Daniel B. Thomas. 2021. A Giant Oligocene Fossil Penguin from the North Island of New Zealand. Journal of Vertebrate Paleontology. e1953047. DOI: 10.1080/02724634.2021.1953047 

[Botany • 2019] Magnolia napoensis (Magnoliaceae: sect. Talauma) • A New Species from the Amazonian Lowlands of Ecuador and Peru

Magnolia napoensis F.Arroyo, Á.J.Pérez & A.Vázquez,

in Arroyo, Pérez, Machoa, ... et Vázquez-García, 2019.
Magnolia napoensis, a new species from the Amazonian lowlands of Ecuador and Peru is described and illustrated. This species belongs to subsection Talauma; it is similar to M. rimachii in leaf shape but differs from the latter in being taller with a larger diameter and having fewer lateral leaf veins, more numerous hypsophylls, larger flowers, longer outer petals, more numerous stamens and fruits ovoid and ribbed vs. subglobose and smooth. The new species differs from M. neillii by its leaves with fewer lateral veins, glabrous petioles and terminal internodes, more numerous hypsophylls, fewer stamens and ovoid fruits of smaller size, with fewer carpels. Magnolia napoensis is assessed as endangered (EN B2ab(iii)) in accordance with the IUCN criteria.

Keywords: Amazonian lowlands, Ecuador, Magnolia, Peru, Talauma, Magnoliids

FIGURE 3. Magnolia napoensis F.Arroyo, Á.J.Pérez & A.Vázquez.
A. Habit. B. Bract in flower bud. C. Flower bud. D. Leaves with flower at female phase. E. Efrén Merino climbing the trunk. F. Flower at female phase. G. Stamens and stigmas.
 Photographs A-G by Alex Dahua, December 2015, at Sarayaku, Pastaza, Ecuador, Dahua-Machoa et al. 2.

FIGURE 4. Magnolia napoensis F.Arroyo, Á.J.Pérez & A.Vázquez.
A. Sepals (upper row) and petals (middle and lower row); B-C Fruit. D. Fruit axis with seeds hanging from a thread-like white funiculum. E. Fruit starting dehiscing. F. Fruit showing circumscissile dehiscence. G. Fruit axis without seeds.

Magnolia napoensis F.Arroyo, Á.J.Pérez & A.Vázquez, sp. nov.

Etymology and ethnobotany:—This species is named after Napo province, Ecuador, where the type material and other collections are located. It is known locally in Kichwa as “ahuayura” (large tree). No use has been recorded for this species. 

Frank Arroyo, Álvaro J. Pérez, Alex Dahua Machoa, David A. Neill, Alondra Salome Ortega-Peña and J. Antonio Vázquez-García. 2019. Magnolia napoensis (Subsect. Talauma, Magnoliaceae): A New Species from the Amazonian Lowlands of Ecuador and Peru. Phytotaxa. 427(4); 239–248. DOI: 10.11646/phytotaxa.427.4.2

[Paleontology • 2021] The Scaly Skin of the abelisaurid Carnotaurus sastrei (Theropoda: Ceratosauria) from the Upper Cretaceous of Patagonia

Carnotaurus sastrei  Bonaparte, 1985

in Hendrickx & Bell, 2021.
Illustration: J. Baardse 

The integument of the theropod dinosaur Carnotaurus sastrei from the Upper Cretaceous of Argentina is here described in detail for the first time. The scaly skin of this abelisaurid is the most completely preserved of any theropod and the only example of this form of integument known outside of Tetanurae (excluding footprints). The skin is preserved in the shoulder, thoracic, tail and, possibly, neck regions and consists of medium to large (20–65 mm in diameter) conical feature scales surrounded by a network of low and small (<14 mm) non-imbricating basement scales separated by narrow interstitial tissue. Contrary to previous interpretations, the feature scales are randomly distributed and neither form discrete rows nor show progressive variations in their size along parts of the body. They also show little difference in morphology along the body, although their apices are variously positioned in different body parts. Conversely, the basement scales vary from small and elongated, large and polygonal, and circular-to-lenticular in the thoracic, scapular, and tail regions, respectively. Given the presumed active lifestyle of Carnotaurus and the necessity of shedding excess heat, particularly at large body sizes (>1000 kg), we speculate that the skin may have played a vital role in thermoregulation; a role consistent with integument function in extant mammals and reptiles.
Keywords: Integument, Scales, Abelisauridae, Non-avian Theropoda, Skin

 Christophe Hendrickx and Phil R. Bell. 2021. The Scaly Skin of the abelisaurid Carnotaurus sastrei (Theropoda: Ceratosauria) from the Upper Cretaceous of Patagonia. Cretaceous Research. 128, 104994. DOI: 10.1016/j.cretres.2021.104994 

[PaleoMammalogy • 2021] Vishnuonyx neptuni • A New early late Miocene Species of Vishnuonyx (Carnivora: Mustelidae: Lutrinae) from the Hominid Locality of Hammerschmiede, Bavaria, Germany

Vishnuonyx neptuni 
Kargopoulos, Valenciano, Kampouridis, Lechner & Böhme, 2021

This study presents a new species of a large-sized lutrine from the upper Miocene hominid locality of Hammerschmiede, Vishnuonyx neptuni sp. nov., reporting the first occurrence of the genus in Europe and its most northern and western record. The new species differs from the already known members of the genus in size (intermediate between the African Vishnuonyx? angololensis and the Asiatic Vishnuonyx chinjiensis) and morphology, in particular in the larger P4 hypocone, the primitive morphology of M1 (paraconule present, enlarged protoconule and metaconule, labial expansion at the paracone area), the shorter and more robust lower premolars and the wider m1 trigonid. We hypothesized that the dispersal event that led to the expansion of the genus in Europe seems to be correlated with the water connection between Paratethys and the Mesopotamian Basin during the Konkian, between 13.4 and 12.65 Ma. In terms of paleoecology, it is here suggested that this form was feeding mainly on fish and less on bivalves or plant material, resembling the extant giant otter, Pteronura brasiliensis.

Vishnuonyx neptuni sp. nov.

Nikolaos Kargopoulos, Alberto Valenciano, Panagiotis Kampouridis, Thomas Lechner and Madelaine Böhme. 2021. New early late Miocene Species of Vishnuonyx (Carnivora, Lutrinae) from the Hominid Locality of Hammerschmiede, Bavaria, Germany. Journal of Vertebrate Paleontology. e1948858. 

Researchers in Germany discover a new species of otter

Thursday, September 16, 2021

[Herpetology • 2021] Chilabothrus ampelophis • A Small New Arboreal Species of west Indian Boa (Serpentes: Boidae) from southern Hispaniola

Chilabothrus ampelophis 
Landestoy, Reynolds & Henderson, 2021

 DOI: 10.3099/MCZ67.1 

Thirteen species of West Indian boas (Chilabothrus) are distributed across the islands of the Greater Antilles and Lucayan Archipelago. Hispaniola is unique among this group of islands in having more than two species of Chilabothrus—three are currently recognized. Here we describe a fourth species from Hispaniola, a newly discovered distinctive species of small boa from the dry forest of the Barahona Peninsula, southwestern Dominican Republic, near the border with Haiti. This new species resembles in body size and in other aspects its closest relative Chilabothrus fordii (Günther 1861), with which it appears to be allopatric. The new species, which we describe as Chilabothrus ampelophis sp. nov., differs from C. fordii in body, head, and snout shape; in scalation; in both coloration and color pattern; and in phylogenetic uniqueness. Some relevant meristic characters from C. ampelophis sp. nov. fall between C. fordii and C. gracilis (Fischer, 1888), accentuating the morphological and likely ecological differences from its sister species C. fordii. The discovery of this new species is especially important as it appears to be among the smallest boid (Boidae) species, has an arboreal specialization, and is found in a very restricted and highly threatened habitat.

Figure 5. Head shape and scutellation in dorsal view of
A, Chilabothrus fordii (MNHNSD 23.3904).
B-F, type series of Chilabothrus ampelophis sp. nov.: MNHNSD 23.3900, KUH 352337, MNHNSD 23.3902, MNHNSD 23.3901, MCZ R-197400, respectively.
Head-scale formula is indicated by light shading (intersupraocular or frontal scales) and numbers (3-1-2; F = frontal); dark shading highlights supraocular scales. Scale bars = 5 mm.

Figure 2. Chilabothrus ampelophis sp. nov.
Clockwise from top: KUH 352337 (5 December 2020), MNHSD 23.3901 (19 November 2020), MNHSD 23.3901 (19 November 2020).

Figure 6. Head and snout profiles of left, Chilabothrus ampelophis sp. nov. (MCZ R-197400) and right, C. fordii (MNHNSD 23.3906).
Note the flat head and protruding eyes and supraoculars above the level of frontal region in C. ampelophis; this region is convex with a gradually tapering snout in C. fordii.

Figure 7. Dorsal patterns of A, Chilabothrus ampelophis sp. nov. (MNHNSD 23.3901) and B, C. fordii (MNHNSD 23.3906).
Note the differences in coloration and shape of the primary elements: basically and predominantly a zigzag in C. ampelophis and ovate to subcircular blotches in C. fordii. Sizes are not to scale.

Chilabothrus ampelophis sp. nov.
Hispaniolan Vineboa

Etymology. The epithet is from ancient greek ampelos, meaning vine, in allusion to the slender body and head shape, which is rather unusual for the genus, and for the relative abundance of vines in the dry rocky habitat at the type locality. The suffix -ophis refers to a snake, hence the epithet is translated as ‘‘vinesnake.’’ 

Figure 8. Habitat of Chilabothrus ampelophis sp. nov. in the southwestern corner of the Dominican Republic.
A, aerial drone photo from March 2021 showing general habitat consisting of forested rolling hills from 200-to 400-m elevation where all specimens of C. ampelophis sp. nov. were found.
B and C, photos showing habitat characteristics of the type locality for C. ampelophis sp. nov.
D, agricultural encroachment along the foothills of the type locality.